Electrical connector



F. w. WAHI.

`ELECTRICAL CONNECTOR March 17, 1964 Filed Feb. 9, 1962 ha E Us Rm wh mw V. mW K K R .L o rr. R C' United States Patent O y3,125,630 Patented Mar. 17, 1964 ice 3,125,630 ELECTRICAL CONNECTOR Frederick W. Wahl, West Chester, Pa., assign'or to AMI Incorporated, Harrisburg, Pa. Filed Feb. 9, 1962, Ser. No. 172,132 4 Claims. (Cl. 174-94) In the art of securing electrical connectors together by crimping, it is often desirable to secure large-sized connectors together in a manner to achieve excellent tensile characteristics, while at the same time having good conductivity. While good conductivity may be achieved without severe deformation of the connector and conductor, it is generally necessary to cold-forge the connection into intimate metal-to-metal engagement to achieve good tensile characteristics.

It is an object of this invention to provide a set of inserts in an electrical connector which will bite into the conductor and achieve good tensile strength without the investment of high crimping forces. Also, the connector is designed so that part of it may be crimped to the conductor without excessively high crimping pressure.

It is also an object of this yinvention to design such a connector which is adaptable for use in connectors having a steel strand. The connector is adapted to have the insert bite into the steel strand for good mechanical strength, while another part of the connector is crimped to the conductor to achieve good conductivity.

It is also an object of this invention to make such an insert out of a plurality of identical pieces which may be fitted together to form a tubular conductor-grasping section.

Other objects and attainments of the present invention will become apparent to those skilled in the art upon a reading of the following detailed description when taken in conjunction with the drawings in which there is shown and described an illustrative embodiment of the invention; it is to be understood, however, that this embodiment is not intended to be exhaustive nor limiting of the invention but is given for purposes of illustration in order that others skilled in the art may fully understand the invention and the principles thereof and the manner of applying it in practical use so that they may modify it in various forms, each as may be best suited to the conditions of a particular use.

In the drawings:

FIGURE 1 is a perspective exploded view of one of the inserts;

FIGURE 2 is a view similar to FIGURE 1 showing the insert assembled and in exploded condition from the other components of the connector;

FIGURE 3 is a longitudinal center section of the insert fitted within an aluminum tube;

FIGURE 4 is a view similar to FIGURE 3 showing the connector crimped on a conductor;

FIGURE 5 is a section taken through plane 5-5 of FIGURE 3;

FIGURE 6 is another embodiment showing a threepiece insert; and

FIGURE 7 is a perspective View of a section of aluminum cable reinforced with steel strands.

As shown in FIGURE 7, a typical example of a conductor useful with the connector of this invention includes aluminum-stranded wires 10 having a central steel core 12, which may be stranded or solid, projecting from one end thereof. The connector, generally designated at 14, includes an outer aluminum tubular member 16 with a central insert for grasping the steel core 12.

This insert is comprised of four segments (FIGURE 1), designated 18. Since al1 of the segments are identical, only one need be described. As shown in FIGURE 1, the segment 13 has a planar inner surface 20, with a series of serrations thereon. The outside surface of the segment is arcuate as at 22 (FIGURE 1). The length of the arc is roughly one-fourth the circumference of the outside surface of the insert so that four such segments comprise a tubular insert.

Again considering the planar inner surface 20, a series of finger-like members or projections 23 extend from each side with a series of recesses 24 therebetween. As shown in FIGURE 3, the projections 23 on one side of the longitudinal axis of the surface are opposite the recesses 24 on the other side. This staggered relationship permits assembling the segments so that the projections on one segment correspond to the recesses on the adjacent segment. The ends of the segments are tapered at 26 and 28 to guide the wire therein.

As shown in FIGURES 2 and 5, when the four segments are assembled to make a tubular insert, four iiat inner surfaces 20 (FIGURE 2) cooperate to form four points of tangency to the wire -to be secured therein.

A pair of frusto-pyramidal members 30 having a circular base may be aixed to the taperedk inner portions 26 and 28 of the ends of the inserts in the assembly.

When the segments 18 are properly assembled with the members 30, the entire insert is placed within the tube 16, and the outer member 30 is flared into the sleeve 16 to hold the insert in place (FIGURE 3). A dimple 32 may be formed inwardly of the tube 16 to keep the pyramidal members stationary while crimping. An inhibitor 27 is coated on the inner wall of the sleeve 16 ,as shown in FIGURE 3.

In use with an aluminum-stranded wire with a central steel core, it is advantageous to use a connector having an aluminum outer tube 16, aluminum frusto-pyramidal members 30, and powdered metal insert segments 18. (The term powdered metal refers to objects made by the powdered metallurgica process, which generally are easily manufactured, very hard and highly frangible. A suitable composition includes 97.15% Fe, 2% Cu, .85% C; cf., Physical Properties of Reduced Iron Powder Plug Graphite and Copper, by George Stern, published in The Iron Age, March 24, 1949.)

Operation-When it is desired to secure a wire in the connector, the central steel core 12 is inserted centrally of the surfaces 20. The aluminum strands abut the member 30 and are contained in the outer aluminum tube 16. Crimping dies (not shown) are applied to the outer aluminum shell 16 in the region of the insert to crack the segments 18 and cause the segments 18 to be compressed onto the core 12 so that the serrations on the planar surface bite into the steel strands. The outer aluminum tube 16 is deformed against the segments 18 so that the deformed condition is retained.

Additionally, crimping dies are applied to the outer aluminum tube 16 in the area of the aluminum strands 10. This performs an aluminum-to-aluminum crimped connection which results in good electrical conductivity.

FIGURE 6 illustrates a similar connector having three segments 18 rather than four. The aluminum tube 16' surrounds the segments which are identical with those shown in FIGURES 1-3. The wire may be inserted centrally of the segments and the outer tube 16 is compacted in the area of the insert, as Well as in the area of the wire, to form a good mechanical and electrical connection. The inserts are retained in position by the same means as the embodiment of FIGURES 1-5.

It is noted that, by making the inserts of interleaving segments, they may be expanded or contracted to accommodate a greater range of wire sizes.

Changes in construction will occur to those skilled in the art and various apparently different modifications and embodiments may be made without departing from the scope of the invention. The matter set forth in the foregoing description and accompanying drawings is offered by way of illustration only. The actual scope of the invention is intendedA to be dened in the following claims when viewed in their proper perspective against the prior art.

I claim:

1. An electrical connector adapted to be secured to an electrical conductor, said connector comprising an outer cylindrical tube of soft metal, and an insert located within said tube, said insert comprising a plurality of segments which are complementary to form an inner cylinder, each of said segments having an outer arcuate surface and an inner planar surface, said inner planar surfaces having a plurality of serrations thereon, each side of the planar portion having a series of projections with intermediate recesses therebetween, the recesses on one side corresponding with the projections on the opposite side so that each segment is identical, and the projections of one segment adapted to t into the recesses on another segment whereby a plurality of segments may be interleaved within said tube to accept an electrical conductor and secured thereto through pressure-forging.

2. The device of claim 1 including a pair of tapered members having central openings at the apex of the taper which fit onto each end of the inner cylinder formed by4 said insert to retain the insert in place and guide the conductor when it is being introduced therein.

3'. An electrical connector adapted to be secured to a conductor including: a central insert portion adapted to be crimped onto the conductor and bite securely into the conductor, said insert portion comprising a plurality of identical intertting segments forming a tubular-like member, said segments being made of a material harder than the material of the conductor, each of said segngerlike portions on one side being'opposite a recessed portion on the other side so that the identical segments may be interleaved to form a central opening in the insert, each of said insert segments being tapered at their ends from the inner planar surface outwardly to the outer arcuate surface, whereby the central opening of the insert may be varied to accommodate a range of wire sizes and an outer tubular member surrounding said insert and being longer than said insert, adapted to be crimped to said conductor, and means for retaining said insert in said tubular member whereby pressure may be exerted on the tubular member in the region of the insert to collapse the insert onto the conductor.

4. The device of claim 3 wherein said retaining means further includes a pair of frusto-pyramidal tapered members having pyramidal faces equal in number and taper configuration to the corresponding insert segments whereby said segments are regularly spaced about that portion of said conductor which the central opening of the insert accommodates.

References Cited in the le of this patent UNITED STATES PATENTS 2,279,677 Heinrich Apr. 14, 1942 2,576,528 Matthysse Nov. 27, 1951 3,052,750 Cobaugh Sept. 4, 1962 

1. AN ELECTRICAL CONNECTOR ADAPTED TO BE SECURED TO AN ELECTRICAL CONDUCTOR, SAID CONNECTOR COMPRISING AN OUTER CYLINDRICAL TUBE OF SOFT METAL, AND AN INSERT LOCATED WITHIN SAID TUBE, SAID INSERT COMPRISING A PLURALITY OF SEGMENTS WHICH ARE COMPLEMENTARY TO FORM AN INNER CYLINDER, EACH OF SAID SEGMENTS HAVING AN OUTER ARCUATE SURFACE AND AN INNER PLANAR SURFACE, SAID INNER PLANAR SURFACES HAVING A PLURALITY OF SERRATIONS THEREON, EACH SIDE OF THE PLANAR PORTION HAVING A SERIES OF PROJECTIONS WITH 